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3 years ago

In which situations is work being done? ( You can pick more than 1)

2 answers:

7 0

A balloon expanding would count as work because it is moving and none of the others are. However, I think that James pedaling also works because at least he is using his leg muscles even though he's not moving. He is working because he is exercising himself and that count as working. I would chose James over all of them.

Ivan3 years ago

4 0

Answer:

Andy’s car rolls down a hill with the engine off.

A balloon expands as it is heated by the Sun.

James pedals a stationary exercise cycle that doesn’t move.

Explanation:

1). Hannah leans against her locker, but it doesn’t move.

Since Hannah is at rest and there is no displacement so there is no work on Hannah by the contact force

2). Andy’s car rolls down a hill with the engine off.

Since car is rolled down the hill so here work is done on the car by force of gravity on the car

3). A wind turbine stands still on a sunny, windless day.

Since wind turbine is at rest so there will be no work on the turbine due to force of wind

4). A balloon expands as it is heated by the Sun.

Here since the volume of balloon is increased so work is done by the internal air of balloon to expand it.

5). James pedals a stationary exercise cycle that doesn’t move.

While pedaling since the force exerted by the cyclist and the pedal goes down so work is done by the cyclist to move the pedal up and down

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How can geo thermal energy be used ?

jek_recluse [69]

Answer:

Geothermal energy can heat, cool, and generate electricity: Geothermal energy can be used in different ways depending on the resource and technology chosen—heating and cooling buildings through geothermal heat pumps, generating electricity through geothermal power plants, and heating structures through direct-use

Explanation:

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2 years ago

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At the top of a giant swing on the gymnastics high bar, candy's velocity is 1 m/s, and she is 3.5 m high. if candy's mass is 50

Allushta [10]

The total mechanical energy is the sum of the kinetic energy and the gravitational potential energy:
$E=K+U= \frac{1}{2}mv^2 +mgh$
where m=3.5 kg is Candy's mass, v=1 m/s is her velocity and h=3.5 m is her height. If we replace these numbers, we find the mechanical energy of the system:
$E= \frac{1}{2} (50 kg)(1m/s)^2 + (50 kg)(9.81 m/s^2)(3.5 m)=1742 J =1.74 kJ$

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3 years ago

An AC voltage source and a resistor are connected in series to make up a simple AC circuit. If the source voltage is given by ΔV

ra1l [238]

Answer:

t = 5.48 × 10⁻³ s

Explanation:

Given:

ΔV = ΔVmax × sin(2πft)

frequency, f = 16.9Hz

thus,

ΔV = ΔVmax × sin(2π×16.9×ft)

Now,

Let 'R' be the resistance

Also according to the ohms law

i = V/R

where,

i = current

V = voltage

hence,

$i=\frac{\Delta V_{max}sin(2\pi \times 16.9\times t)}{R}$

also, given at time 't' the current in the circuit is 55.0% of the peak current

thus

$i=\frac{55}{100}\times \frac{\Delta V_{max}}{R}=0.55\times \frac{\Delta V_{max}}{R}$

thus,

$0.55\times \frac{\Delta V_{max}}{R}=\frac{\Delta V_{max}sin(2\pi \times 16.9\times t)}{R}$

$0.55=sin(2\pi \times 16.9\times t)}$

$0.5823=(2\pi \times 16.9\times t)}$

t = 5.48 × 10⁻³ s (Answer)

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3 years ago

Two thermometers are calibrated, one in de

zlopas [31]

-40 c = -40 f but k would be 233.15

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3 years ago

A research submarine can withstand an external pressure of 62 megapascals (million pascals) all the while maintaining a comforta

Alex

Answer:

The depth will be equal to 6141.96 m

Explanation:

pressure on the submarine $P_{sea}$ = 62 MPa = 62 x 10^6 Pa

we also know that $P_{sea}$ = ρgh

where

ρ is the density of sea water = 1029 kg/m^3

g is acceleration due to gravity = 9.81 m/s^2

h is the depth below the water that this pressure acts

substituting values, we have

$P_{sea}$ = 1029 x 9.81 x h = 10094.49h

The gauge pressure within the submarine $P_{g}$ = 101 kPa = 101000 Pa

this gauge pressure is balanced by the atmospheric pressure (proportional to 101325 Pa) that acts on the surface of the sea, so it cancels out.

Equating the pressure $P_{sea}$ , we have

62 x 10^6 = 10094.49h

depth h = 6141.96 m

7 0

3 years ago